The I See Lead People blog has a photo tutorial on making a garden patch.
Here’s a photo tutorial on making a ruined building. It’s intended for Mordheim, but the technique are universal.
Here’s a photo tutorial on making some very effective plowed fields terrain for your wargames tabletop.
Here’s a nice photo essay on building a red planet terrain board.
Roundwood’s World has an excellent photo illustrated post on how he built a trenches terrain board. It’s something I’ve always wanted to do.